Weeds are tenacious: Give them an inch — or even less — and they’ll take a mile. Weeds can develop even in the smallest cracks on your patio, ruining the appearance of the space. Pulling them by hand is backbreaking work, and lots of home gardeners today are too environmentally conscious to spray chemicals. An environmentally friendly solution employs salt water to kill weeds.
Why Salt Works
Plant roots absorb water, and when that water contains salt, they absorb the salt too. Water moves through the walls of plant cells. The high concentration of salt outside the plant cells leads to the water within the mobile to move out of the cell, making them collapse. In essence — and quite ironically — the plant dies of dehydration. Salt sprinkled directly onto the soil has the exact same effect, but water helps it sink into the soil and be taken up faster by the plant.
Mix It Up
Create a solution by adding 1 cup of salt to 2 cups of boiling water. Stir until the salt is dissolved and then pour the still-hot water right onto the weeds. Because salt will dissolve in cold water, you don’t have to heat the water should youn’t need to utilize warm water, but also the heat in the water will destroy the weeds faster. Salt isn’t discriminatory. If you have nearby, desirable plants — like those that develop along the outer edges of your patio — take care not to get the salt water on these plants, since it will destroy them also.
Things to Consider
Salt destroys the soil for other plants. If you believe you may get rid of the patio and develop plants in that location in the near future — or even a couple of years down the trail — think twice about having salt water to kill the weeds. Consider runoff too. If your patio slopes, then the salt water may run off the patio and contaminate your turf grass or other desirable areas of the landscape, killing the plants and destroying the soil.
If you’re worried about destroying the soil, use boiling water with no salt added to destroy the weeds. Boiling water applied directly to weeds kills them in just a couple of days, according to the University of Washington Botanic Gardens website. The only downside of this procedure is that — unlike salt water, which prevents weeds from regrowing in the cracks — boiling water has to be reapplied when the weeds begin to grow back.